Achievement of Target Gain Larger than Unity in an Inertial Fusion Experiment

On December 5, 2022, an indirect drive fusion implosion on the National Ignition Facility (NIF) achieved a target gain G_{target} of 1.5. This is the first laboratory demonstration of exceeding "scientific breakeven" (or G_{target}>1) where 2.05 MJ of 351 nm laser light produced 3.1 MJ of total fusion yield, a result which significantly exceeds the Lawson criterion for fusion ignition as reported in a previous NIF implosion [H. Abu-Shawareb et al. (Indirect Drive ICF Collaboration), Phys. Rev. Lett. 129, 075001 (2022)PRLTAO0031-900710.1103/PhysRevLett.129.075001]. This achievement is the culmination of more than five decades of research and gives proof that laboratory fusion, based on fundamental physics principles, is possible. This Letter reports on the target, laser, design, and experimental advancements that led to this result.

Lawson Criterion for Ignition Exceeded in an Inertial Fusion Experiment

For more than half a century, researchers around the world have been engaged in attempts to achieve fusion ignition as a proof of principle of various fusion concepts. Following the Lawson criterion, an ignited plasma is one where the fusion heating power is high enough to overcome all the physical processes that cool the fusion plasma, creating a positive thermodynamic feedback loop with rapidly increasing temperature. In inertially confined fusion, ignition is a state where the fusion plasma can begin "burn propagation" into surrounding cold fuel, enabling the possibility of high energy gain. While "scientific breakeven" (i.e., unity target gain) has not yet been achieved (here target gain is 0.72, 1.37 MJ of fusion for 1.92 MJ of laser energy), this Letter reports the first controlled fusion experiment, using laser indirect drive, on the National Ignition Facility to produce capsule gain (here 5.8) and reach ignition by nine different formulations of the Lawson criterion.

Highly pathogenic avian influenza virus H5N6 (clade 2.3.4.4b) has a preferable host tropism for waterfowl reflected in its inefficient transmission to terrestrial poultry

Highly-pathogenic avian influenza virus (HPAIV) H5N6 (clade 2.3.4.4b) incurred into Europe in late 2017 and was predominantly detected in wild birds, with very few terrestrial poultry cases. Pekin ducks directly-infected with a UK virus (H5N6-2017) were donors of infection to investigate contact transmission to three recipient species: Ducks, chickens and turkeys. H5N6-2017 transmission to ducks was 100% efficient, but transmission to in-contact galliforme species was infrequent and unpredictable, thereby reflecting the European 2017-2018 H5N6 epidemiology. Although only two of 28 (7%) infected ducks died, the six turkeys and one chicken which became infected all died and displayed systemic H5N6-2017 dissemination, while pathogenesis in ducks was generally milder. Analysis of H5N6-2017 progeny in the contacts revealed no emergent polymorphisms in an infected duck, but the galliforme species included changes in the polymerase (PB2 A199T, PA D347A), matrix (M1 T218A) and neuraminidase genes (T88I). H5N6-2017 environmental contamination was associated with duck shedding.

Genome-wide association study identifies variants associated with hair length in Brangus cattle

Thermal stress limits beef cattle production and a shorter hair coat is a key thermoregulative adaptation that allows cattle to lose heat more efficiently. The objective of this study was to identify genetic variants associated with the length of the undercoat and topcoat of cattle utilizing 1456 Brangus heifers genotyped with the Bovine GGP F250 array. Seven SNPs in the PCCA gene were significantly associated with undercoat length. PCCA belongs to the biotin transport and metabolism pathway. Biotin deficiency has been reported to cause hair loss. Four SNPs in an 110 kb including a missense mutation in the PRLR gene were significantly associated with topcoat length. Whereas the association of this polymorphism with hair length is novel, the SLICK mutation in PRLR has previously been demonstrated to significantly impact hair length in cattle. These newly detected genetic variants may contribute to a shorter hair coat and more thermotolerant animals.

Diagnostic interaction between bovine tuberculosis (bTB) and Johne's disease in bTB highly prevalent dairy farms of Uruguay

The consolidation of the dairy industry, with increase in sizes, density and productivity of the herds, was associated to unprecedented bovine tuberculosis (bTB) prevalence levels in dairy herds in Uruguay, where Johne's disease (JD), another mycobacterial disease, is also prevalent. Here, we aimed to characterize the association between bTB- and JD-diagnostic results in two heavily bTB- and JD-coinfected dairy herds. Results from bTB-intradermal tests and JD-ELISA in 686 cows indicated a significantly (P < 0.001) higher frequency of bTB-positive animals in the JD-positive population, in which a significantly lower agreement between the caudal and cervical comparative intradermal tests was observed, compared to the JD-negative population. These findings suggest a significant association between the detection of these mycobacterial diseases, that may affect the performance of the routine bTB diagnostic tests performed in dairy herds in Uruguay.

Laryngospasm, central and obstructive apnea during seizures: Defining pathophysiology for sudden death in a rat model

Seizure spread into the autonomic nervous system can result in life-threatening cardiovascular and respiratory dysfunction. Here we report on a less-studied consequence of such autonomic derangements-the possibility of laryngospasm and upper-airway occlusion. We used parenteral kainic acid to induce recurring seizures in urethane-anesthetized Sprague Dawley rats. EEG recordings and combinations of cardiopulmonary monitoring, including video laryngoscopy, were performed during multi-unit recordings of recurrent laryngeal nerve (RLN) activity or head-out plethysmography with or without endotracheal intubation. Controlled occlusions of a tracheal tube were used to study the kinetics of cardiac and respiratory changes after sudden obstruction. Seizure activity caused significant firing increases in the RLN that were associated with abnormal, high-frequency movements of the vocal folds. Partial airway obstruction from laryngospasm was evident in plethysmograms and was prevented by intubation. Complete glottic closure (confirmed by laryngoscopy) occurred in a subset of non-intubated animals in association with the largest increases in RLN activity, and cessation of airflow was followed in all obstructed animals within tens of seconds by ST-segment elevation, bradycardia, and death. Periods of central apnea occurred in both intubated and non-intubated rats during seizures for periods up to 33s and were associated with modestly increased RLN activity, minimal cardiac derangements, and an open airway on laryngoscopy. In controlled complete airway occlusions, respiratory effort to inspire progressively increased, then ceased, usually in less than 1min. Respiratory arrest was associated with left ventricular dilatation and eventual asystole, an elevation of systemic blood pressure, and complete glottic closure. Severe laryngospasm contributed to the seizure- and hypoxemia-induced conditions that resulted in sudden death in our rat model, and we suggest that this mechanism could contribute to sudden death in epilepsy.

Delayed presentation of a lumbar artery pseudoaneurysm resulting from isolated penetrating trauma

Lumbar artery pseudoaneurysms are infrequent complications of penetrating trauma. When present, they are often accompanied by other injuries; however, we report the case of an isolated traumatic lumbar artery aneurysm resulting from a single knife stab. The lesion was successfully treated with endovascular microcoil embolization. While these injuries are uncommon, the surgeon must maintain a high index of suspicion, even with seemingly uncomplicated injuries, as a missed traumatic pseudoaneurysm may be life threatening.

Particle-size dependent effects in the Balb/c murine model of inhalational melioidosis

Deposition of Burkholderia pseudomallei within either the lungs or nasal passages of the Balb/c murine model resulted in different infection kinetics. The infection resulting from the inhalation of B. pseudomallei within a 12 μm particle aerosol was prolonged compared to a 1 μm particle aerosol with a mean time-to-death (MTD) of 174.7 ± 14.9 h and 73.8 ± 11.3 h, respectively. Inhalation of B. pseudomallei within 1 μm or 12 μm particle aerosols resulted in a median lethal dose (MLD) of 4 and 12 cfu, respectively. The 12 μm particle inhalational infection was characterized by a marked involvement of the nasal mucosa and extension of bacterial colonization and inflammatory lesions from the olfactory epithelium through the olfactory nerves (or tracts) to the olfactory bulb (100%), culminating in abscessation of the brain (33%). Initial involvement of the upper respiratory tract lymphoid tissues (nasal-associated lymphoid tissue (NALT) and cervical lymph nodes) was observed in both the 1 and 12 μm particle inhalational infections (80-85%). Necrotising alveolitis and bronchiolitis were evident in both inhalational infections, however, lung pathology was greater after inhalation of the 1 μm particle aerosol with pronounced involvement of the mediastinal lymph node (50%). Terminal disease was characterized by bacteraemia in both inhalational infections with dissemination to the spleen, liver, kidneys, and thymus. Treatment with co-trimoxazole was more effective than treatment with doxycycline irrespective of the size of the particles inhaled. Doxycycline was more effective against the 12 μm particle inhalational infection as evidenced by increased time to death. However, both treatment regimes exhibited significant relapse when therapy was discontinued with massive enlargement and abscessation of the lungs, spleen, and cervical lymph nodes observed.

Characterisation of experimental infections of domestic pigs with genotype 2.1 and 3.3 isolates of classical swine fever virus

The early identification of classical swine fever epizootics is hampered by difficulties in recognising early signs of infection, due to a lack of specific clinical signs. In addition many textbook descriptions of CSF are based on observations of disease caused by historic, mainly genotype 1, strains. Our objective was to improve our knowledge of the diverse range of signs that different CSFV strains can cause by characterising the experimental infection of domestic pigs with both a recent strain of CSFV and a divergent strain. Conventional pigs were inoculated with a genotype 2.1 isolate, that caused an outbreak in the UK in 2000, and a genotype 3.3 strain that is genetically divergent from European strains. This latter strain is also antigenically distinct as it is only poorly recognised by the CSFV-specific monoclonal antibody, WH303. Transmission was monitored by use of in-contact animals. Clinical, virological and haematological parameters were observed and an extended macro- and histopathological scoring system allowed detailed characterisation of pathological lesions. Infection with the genotype 2.1 isolate resulted in a similar outcome to other recent genotype 2 European strains, whereas the genotype 3.3 strain produced fewer and delayed clinical signs, notably with little fever. This strain would therefore be particularly difficult to detect in the early stages of infection and highlights the importance of encouraging early submission of samples for laboratory diagnosis. As representatives of recent and divergent CSFV isolates, these strains are good candidates to study the pathogenesis of current CSFV isolates and as challenge models for vaccine development.

Detection of high levels of European bat lyssavirus type-1 viral RNA in the thyroid gland of experimentally-infected Eptesicus fuscus bats

Two common bat lyssavirus species have been identified in many European countries: European bat lyssavirus type-1 and -2 (EBLV-1 and EBLV-2). Only limited knowledge on the susceptibility of the natural EBLV-hosts, insectivorous bats, to lyssavirus infection is available. Our study was undertaken to evaluate the susceptibility and pathology associated with an EBLV-1 infection in Eptesicus fuscus following different routes of virus inoculation including intracranial (n = 6), intramuscular (n = 14), oral (n = 7) and intranasal (n = 7). Blood and saliva samples were collected from all bats on a monthly basis. Four bats inoculated intracranially developed rabies with a mean of 11 days to death, whilst seven bats inoculated intramuscularly developed rabies, with an extended incubation period prior to death. We did not observe any mortality in the oral (p.o.) or intranasal (i.n.) groups and both groups had detectable levels of virus neutralizing antibodies (data not shown). Virus shedding was demonstrated in the saliva by virus isolation and the detection of viral RNA in ill bats, particularly immediately prior to the development of disease. In addition, the presence of virus and viral RNA was detected in the thyroid gland in bats challenged experimentally with EBLV-1, which exceeded that detected in all other extra-neural tissue. The significance of detecting EBLV-1 in the thyroid gland of rabid bats is not well understood. We speculate that the infection of the thyroid gland may cause subacute thyroiditis, a transient form of thyroiditis causing hyperthyroidism, resulting in changes in adrenocortical activity that could lead to hormonal dysfunction, thereby distinguishing the clinical presentation of rabies in the rabid host.

Histological observations of bovine tuberculosis in lung and lymph node tissues from British deer

Deer are recognized as hosts of Mycobacterium bovis and assessing the role of wild cervids in perpetuating tuberculosis among cattle has motivated extensive research on several continents. In this paper, the histopathology of lymph node and lung tuberculous granulomas in M. bovis positive British deer is presented. The overall aim was to seek further insights into the potential for onward transmission from infected deer to other species, including cattle. Samples were obtained from an extensive survey of wild mammals in South-West England and from statutory tuberculosis surveillance. M. bovis culture-positive samples were characterised microscopically as to their stage of lesion advancement, number of acid-fast bacilli and granuloma encapsulation. Seventy percent of the deer developed granulomas containing far greater numbers of M. bovis bacilli than typically reported in cattle. Red and fallow deer had the largest number of poorly encapsulated granulomas often containing many hundreds of bacilli. The results are consistent with infected wild British deer being a potential source of environmental contamination and onward transmission to other species. However, further work on levels of bacillary shedding is required before this can be confirmed.

Inflammatory responses in the nervous system of mice infected with a street isolate of rabies virus

Rabies virus causes severe encephalitis that is invariably fatal for the victim. However, the contribution of the virus and the host to damage of the CNS is unclear. In order to investigate this we studied the neuropathology and CNS gene expression patterns in a murine model of rabies using a 'street' isolate RV61. This virus was derived from a human case of disease. In this model, infection of the CNS progresses rapidly following inoculation in the periphery, leading to extensive virus replication in the brain and the development of disease. However, previous studies have found little evidence of inflammation and lymphocyte infiltration in many regions of the CNS of infected mice. During the current study virus replication was detected in the dorsal root ganglia (DRG), spinal cord, brain and salivary gland at 11 days postinfection (dpi). Mononuclear cell infiltration was observed in the DRG and to a lesser extent, the spinal cord. Immunolabelling demonstrated that T-lymphocytes were the dominant population of infiltrating cells. Murine innate immune response gene transcripts were detected in the brain as early as 5 dpi. At 11 dpi, coincidentwith the onset of disease, elevated levels of mRNA transcripts were recorded for type-1 (alpha and beta) and type-2 interferon (gamma) and certain chemokines (CCL5 and CXCL10) with chemotactic properties for T-cells. We suggest that damage to the DRG and spinal cord could be due to a combination of both virus infection and the infiltration of T-cells.

Distribution and activation of T-lymphocyte subsets in tuberculous bovine lymph-node granulomas

The immune response against mycobacterial infections is dependant upon a complex interaction between T lymphocytes and macrophages in the context of the granuloma. For this study, we performed the analysis of 18 stage I or II, and 13 stage III or IV granulomas found in lymph nodes from 8 experimentally and 2 naturally infected cattle. T-cell subpopulations (CD3(+), CD4(+), CD8(+), WC1(+), CD25(+)) were investigated by immunohistochemistry. In the majority of stage I/II lesions, CD8(+) and CD25(+) cells were predominantly found in the lymphocytic outer region of the granuloma, suggesting a possible role for activated CD8(+) cells in the initial attempt to restrain the granuloma growth. CD4(+) T cells appeared equally distributed in the lymphocytic mantle and in the internal areas of the granulomas. WC1(+) cells appeared interspersed among the macrophages. We speculated that this could indicate a role for these 2 subsets in the maintenance and the maturation of the granuloma. In stage III/IV lesions, all of the T-cell subsets investigated appeared interspersed among the mononuclear component of the granulomas. In general terms, there was a higher density of CD8(+) cells compared with CD4(+) cells. However, there was no sense of rimming effect for any of the investigated cell populations.

Women's health centers and minority women: addressing barriers to care. The National Centers of Excellence in Women's Health

New models of care delivery have been developed to better coordinate and integrate healthcare for women. In the United States, one of the challenges is to incorporate the needs of racial and ethnic minority populations into these newer care paradigms. This paper begins with a brief historical review of the experience of racial and ethnic minorities in the American healthcare system to provide a context for discussing barriers and limitations of more traditional models of women's healthcare. Specific approaches used by National Centers of Excellence in Women's Health are presented as examples of strategies that may be implemented by other communities to address these barriers.

Human prostate cancer regulates generation and maturation of monocyte-derived dendritic cells

BACKGROUND

The progression of prostate cancer is accompanied by a marked suppression of the immune system, including the apoptotic death of dendritic cells (DC) responsible for the induction of antitumor immunity. In this study, we evaluated whether prostate cancer might inhibit DC generation and maturation in vitro.

METHODS

DC were generated from peripheral blood monocytes in the presence of the human prostate cell line LNCaP or nonmalignant cells, and characterized by light microscopy, FACScan analysis, and ability to stimulate T-cell proliferation.

RESULTS

Prostate cancer significantly inhibited the conversion of monocytes into DC, which was assessed by the expression of DC markers CD1a and CD83. These cells were weak stimulators of T-cell proliferation, suggesting that DC generated in the prostate cancer microenvironment are functionally inhibited.

CONCLUSIONS

Prostate cancer not only kills mature DC, but also inhibits their generation and maturation, resulting in decreased production of antigen-presenting cells and inhibition of their functional activity.

Neurobehaviour rounds and interdisciplinary education in neurology and psychiatry (698)

Increasing emphasis on interdisciplinary medical treatment and education suggests that something valuable has arisen from medical specialization beyond the further development of specialty knowledge: an integration of specialty knowledge that compliments and extends the integrating aspects of the primary care approach to medicine. Several educational models have been described which serve this function. In this paper the authors describe interdisciplinary clinical teaching, and research team linking neurology, neuroradiology, psychiatry and neuropsychology. The team provides neurobehavioural evaluations and sponsors monthly Neurobehaviour Rounds, an interdisciplinary patient conference that is the main formal teaching vehicle for the programme. After the model had been in place for 1 year, eight of nine neurology residents had Residency In-Service Training Examination scores in behavioural neurology that exceeded their overall average scores. This suggests that encouraging neurology residents to see patients through the eyes of different specialists may have contributed to improvement in their performance on a test of interdisciplinary knowledge. A neurobehavioural programme anchored to a formal neurobehaviour conference may encourage interdisciplinary learning within the related disciplines of neurology, neuropsychology and psychiatry.

Carbachol stimulates inositol phosphate formation in rat thalamus slices through muscarinic M3-receptor activation

In cross-chopped slices from rat thalamus and in the presence of 10 mM LiC1, the cholinergic agonist carbachol stimulated the accumulation of total [3H]inositol phosphates ([3H]IP2 = [3H]IP1 + [3H]IP2 + [3H]IP3). Best-fit values for the concentration-response curve for carbachol after 60 min incubation yielded an EC50 of 44 +/- 6 microM, maximum effect of 199 +/- 6% of basal accumulation and Hill coefficient (nH) of 1.1 +/- 0.1. Carbachol-induced [3H]IPs accumulation was inhibited by 4-diphenylacetoxy-N-methylpiperidine methiodide (4-DAMP; pKi 9.1) and the p-fluoro analogue of hexahydro-sila-difenidol (pF-HHSiD; pKi 8.1). Concentration-response curves for carbachol were shifted to the right in a parallel fashion by pirenzepine (100, 300 and 100 nM). A Schild plot of the data was linear (slope 0.95 +/- 0.04) and yielded a log KD for pirenzepine of -6.8 +/- 0.1. Taken together, these results suggest that carbachol-induced inositol phosphate accumulation in rat thalamus is mediated by muscarinic M3-receptors.

Unit activity of rat basal forebrain neurons: relationship to cortical activity

Unit activity in the magnocellular basal forebrain nucleus was examined to characterize discharge patterns during synchronized and desynchronized electroencephalogram. Two types of basal forebrain neurons were identified by their firing pattern under urethane anaesthesia: bursting and tonic neurons. Bursting neurons (62.9%) were characterized by a spontaneous firing that consisted of periodic bursts of two to six spikes that occurred at 0.3 to 2 Hz and were phase-locked with the electroencephalogram slow waves. Tonic neurons (37.1%) displayed spontaneous single spike firing at 12.1 + or - 1.6Hz. The firing of most of them was not related to the slow waves. Both neuronal types changed their firing patterns during the electroencephalogram desynchronization elicited by either electrical stimulation of the pedunculopontine tegmentum or pinching the rat's tail. Bursting neurons changed from the bursting mode to a tonic mode of discharge pattern, increasing their firing rate, while tonic cells were inhibited during electroencephalogram desynchronization. Multiunit recordings revealed that bursting cells discharged synchronously during periods of electroencephalogram slow waves, but that synchronization disappeared during electroencephalogram desynchronization. No correlation was found between the spike discharges of different tonic cells nor between bursting and tonic cells. However, bursting neurons, but not tonic neurons, were correlated with the spike firings of neocortical neurons during electroencephalogram slow waves. The rhythmic activity of neither neocortical nor bursting basal forebrain cells was found under pentobarbital anaesthesia. The characteristics of the discharge pattern shown by bursting basal forebrain neurons suggest that this type of cell could be cholinergic. Thus, bursting basal forebrain neurons may release acetylcholine in the cortex rhythmically, enhancing the rhythmic activity of cortical neurons during slow-wave sleep. It is concluded that basal forebrain neurons may contribute to the generation of the electroencephalogram slow waves.

Tracheotomy in patients with acquired immunodeficiency syndrome. Is it necessary?

OBJECTIVE

Patients with acquired immunodeficiency syndrome (AIDS) who develop respiratory failure and require mechanical ventilation have mortality rates of 85%. Tracheotomies are performed in this patient population for prolonged intubation. However, to date, objective data on tracheotomy in patients with AIDS are lacking. Tracheotomy in ventilator-dependent patients with AIDS presents risks to patients and exposes surgeons, nurses, and operating room personnel to human immunodeficiency virus-infected blood.

DESIGN

Given these considerations, we retrospectively reviewed our experience with tracheotomy in 10 intubated and ventilator-dependent patients with AIDS.

CONCLUSIONS

Our study shows a mortality rate of 100%. We identify predictive factors and a prognosis that may aid in the treatment of these patients.

Judicial outcome for the intoxicated driver admitted to a regional trauma center

OBJECTIVE

To examine the judicial outcomes for intoxicated drivers who were admitted to regional trauma centers as a result of motor vehicle collisions (MVCs).

METHODS

A retrospective review of the trauma registry of a Level I trauma center was conducted for the period from January 1, 1989, through December 31, 1990. Inclusion criteria for entry into the study were 1) identification of the patient as the driver involved in an MVC, 2) a blood alcohol content (BAC) above 0.10 g/dL, and 3) survival until discharge from the hospital. A total 245 patients from the trauma registry met the inclusion criteria. The number of persons from the submitted list who were later convicted of driving under the influence of alcohol (DUI) was obtained from the Department of Motor Vehicles (DMV) of the Common- wealth of Virginia.

RESULTS

Of the list submitted to the DMV, only nine individuals (3.7%; 95% confidence interval = 1.3--6.0%) were convicted of DUI during the MVCs that led to hospitalization during the study period. During the same time period, the statewide conviction rate for DUI-cited drivers was 85%.

CONCLUSION

Admission to the trauma service at a Level I trauma center may provide a refuge from legal consequences for intoxicated drivers involved in MVCs.

Hyperparathyroidism in black patients: an update

Cervical exploration with removal of the pathologic gland or glands is effective treatment for parathyroid adenomas and hyperplasia. This article reports the results of a retrospective study of 41 patients who underwent elective cervical exploration for primary hyperparathyroidism at Howard University Hospital between 1974 and 1989. Preoperative localization studies for primary neck exploration consisted of an ultrasound of the neck. Removing the diseased gland/glands resulted in the resolution of the patients' symptoms and the return of calcium levels to normal. Complications included transient hypocalcemia, a wound hematoma, and a postoperative death.

Transitory macrophage activation in the granulomatous lesions of Mycobacterium lepraemurium-induced lepromatoid leprosy in the mouse

A kinetic study on the evolution of granulomas that appear in the liver of NIH mice inoculated with 10(8) Mycobacterium lepraemurium by the intraperitoneal route has been performed. The liver was chosen because of its nonlymphoid histology which allowed us to visualize the appearance and maturation of the cell infiltrates generated as a consequence of the mycobacterial infection. The study analyzed both the macrophage activation within the granulomas and the fate of bacilli within the macrophage. The results showed that this mycobacteriosis induces a relatively early macrophage activation (a very likely result of a cell-mediated immune response triggered by the bacilli) that peaks between 45 and 60 days postinoculation, fades thereafter, and practically disappears several days later. Bacilli are susceptible to the microbicidal effects of activated macrophages, but when the macrophages are turned off (probably due to active suppressive mechanisms), the surviving bacilli reinitiate the infection with no further macrophage opposition. As a result, more phagocytes are attracted to the infection sites and the cell infiltrates grow steadily to become confluent, increasing the granuloma fraction and eventually replacing the liver parenchyma. The findings suggest that in murine "leprosy" infection, early immunological changes occur that enable the macrophages present in the granulomas to kill the infecting M. lepraemurium regardless of the eventual lepromatoid evolution of the granulomas. Lepromatoid granulomas in the mouse and lepromatous granulomas in man are equivalent structures in regard to their histology and bacteriology.

Various types of systolic clicks in patients with muscular subaortic stenosis

Four clinical cases of subaortic hypertrophic muscular stenosis are discussed. All four, in addition to a loud systolic murmur, had a loud systolic click. However, the timing of the click and its relationship to the phase of the carotid pulse were different in each case varying from close to medium and to distant (or midsystolic). The comparison of the sound tracing with the carotid tracing demonstrated that, in each case, a sudden change in acceleration was taking place. In one, the click coincided with the onset of the carotid upstroke; in another, with the first peak of the carotid pulse; in the third, with the trough between first and second peak of the pulse; in the last, with a sudden drop of the pulse at mid-systole caused by sudden obstruction to flow. It is concluded that the clicks were caused by rapid changes of acceleration resulting from the abnormal aortic ejection. Thus, the study of the carotid pulse and of the sound tracing are important for a non-invasive diagnosis together with the echo study of the septum and ventricular wall.

Effect of the growth hormone-secreting tumor StW5 on pituitary and adrenal gland function in rats

A growth hormone-secreting tumor (StW5 was implanted into male rats and resulted in a tripling of adrenal weight concomitant with a 30% decrement in pituitary weight. Plasma concentrations of corticosterone in tumor-bearing (TB) rats were significantly elevated at rest or after ACTH injections or the stress of either anesthesia. The rise in plasma concentrations of corticosterone was due mainly to the large increment in adrenal size although a significant increase in adrenal responsiveness to ACTH was demonstrated in vitro. In addition, plasma corticosterone concentrations were higher in TB rats despite both a doubling of the blood volume and a 50% increase in liver capacity to metabolize corticosterone. Pituitary ACTH content was significantly lower in TB rats, but these pituitary glands could still release near-normal quantities of ACTH as shown both by in vitro incubations and adrenal corticosterone output following ether stress.

The blacks of Panama: their genetic diversity as assessed by 15 inherited biochemical systems

Panama's black citizens are culturally and historically divisible into two groups, the Spanish-speaking coloniales and the English-speaking anglos or afro-antillanos. Until recently these groups have been geographically as well as culturally isolated one from the other, although both are predominantly of West and Southwest African origin. Assessment of the genetic diversity within-villages and within language groups reveals as much, possibly somewhat more, diversity in 15 inherited biochemical markers within villages and language groups as that which obtains between villages and language groups. A number of rare variants at the 6-phosphogluconate dehydrogenase, lactate dehydrogenase, and esterase D loci were encountered and are described.